Cellular Therapy for a Rare Genetic Eye Disease
Aniridia-associated keratopathy (ARK) is a progressive disease that develops when limbal stem cells located at the boundary between the cornea and the sclera lose their function. This rare condition, caused by a mutation in the PAX6 gene, affects one in every 40 thousand to 100 thousand people. The lack of limbal stem cells causes conjunctival tissue to advance toward the cornea. This process leads to thickening and clouding of the cornea’s transparent layer, resulting in severe vision loss. Researchers from Moorfields Eye Hospital and University College London (UCL) have developed a cellular tissue scaffold aimed at reversing the condition.
Tissue Scaffold and Two-Stem-Cell Approach
The study, published in JAMA Ophthalmology on July 23, 2026, used a collagen-based tissue scaffold called RAFT-OS. This specially designed carrier structure aims to transport limbal epithelial stem cells and stromal stem cells directly to the damaged area.
In the first trial of the method in humans, transplantation was performed in only one eye of each of nine participants; the untreated other eyes were monitored as the control group. While the clinical success of stem cell therapies in regenerative medicine has also been observed in different fields, this study was the first collagen application in ocular tissue to use two different types of cells together.
Clinical Findings and Improvements in Vision Analysis
At the beginning of the study, the mean ocular surface score (OSS) was measured at 9.4 in the eyes scheduled for treatment and 8.4 in the control eyes. On the ocular surface scale, scores of 0-5 indicate mild, 6-10 moderate, and 11-15 severe disease. In the treated eyes, the mean OSS fell to 5.9 at month 3 and was recorded at 6.7 at the end of month 12. In the untreated control eyes, the score remained at 8.0 at the end of 12 months.
Improvement in Visual Acuity
The treatment’s effect on vision was assessed using ETDRS vision tests.
The mean improvement in vision in the treated eyes was 24 letters. This result corresponds to a marked improvement of approximately 5 lines on a standard eye examination chart. Professor Sajjad Ahmad, who led the study, stated that the first use in the eye of a collagen scaffold containing two different types of stem cells had produced positive results. The research team plans to move on to larger-scale clinical trials so that the method can be accepted as a standard treatment by the United Kingdom’s National Health Service (NHS).